Robust photo-assisted removal of NO at room temperature:Experimental and density functional theory calculation with optical carrier

Photo-assisted SCR(PSCR) offers a potential solution for removal of NO at room temperature. MnTiO_(x)as PSCR catalyst exhibits superior performance with NO removal of 100% at the room temperature. Electron paramagnetic resonance(EPR) analysis revealed the presence of numerous oxygen vacancies on MnTiO_(x). Optical carrier density functional theory(DFT) calculations showed that the threedimensional orbital hybridization of Mn and Ti is significantly enhanced under light irradiation. The MnTiO_(x)catalyst exhibited excellent electron–hole separation ability, which can adsorbe NH_(3)and dissociate to form NH_(2)fragments and H atoms. In-situ diffuse reflectance infrared fourier-transform spectroscopy(DRIFTS) indicated that the optical carrier enhanced NH_(3)adsorption on MnTiO_(x), which makes it possess excellent PSCR activity. This work provided an additional strategy to NO removal with PSCR catalysts and showed potential for use in photocatalysis.

“双一流”建设背景下科教融合实验教学探索--以TiO_(2)光催化降解染料废水实验为例

科教融合的办学理念已经成为“双一流”建设高校科教并重发展的必然选择。将瞬时纳米沉降技术制备多孔TiO_(2)纳米球及其光催化降解染料的研究引入本科教学中,例如大学生研究训练计划(SRP)项目。该综合实验设计内容符合科教融合的发展需求,通过该实验,有助于加深学生对知识点的综合理解,培养学生的创新能力和实践能力。

Overwhelming low ammonia escape and low temperature denitration efficiency via MnOx-decorated two-dimensional MgAl layered double oxides

Low temperature catalysts are attracting increasing attention in the selective catalytic reduction(SCR)of NO with NH3.Mn Ox-decorated Mg Al layered double oxide(Mn/Mg Al-LDO)was synthesized via a facile fast pour assisted co-precipitation(FP-CP)process.Compared to the Mn/Mg Al-LDO obtained via slow drop assisted coprecipitation(SD-CP)method,the Mn/Mg Al-LDO(FP-CP)has excellent activity.The Mn/Mg Al-LDO(FP-CP)catalyst was shown to possess a high NO conversion rate of 76%-100%from 25 to 150℃,which is much better than the control Mn/Mg Al-LDO(SD-CP)(29.4%-75.8%).In addition,the Mn/Mg Al-LDO(FP-CP)offered an enhanced NO conversion rate of 97%and a N2selectivity of 97.3%at 100℃;the NO conversion rate was 100%and the N2selectivity was 90%at 150℃with a GHSV of 60,000 h^-1.The Mn/Mg Al-LDO(FP-CP)catalyst exhibited a smaller fragment nano-sheet structure(sheet thickness of 7.23 nm).An apparent lattice disorder was observed in the HRTEM image confirming the presence of many defects.The H2-TPR curves show that the Mn/Mg Al-LDO(FP-CP)catalyst has abundant reducing substances.Furthermore,the enhanced surface acidity makes the NH3concentration of the Mn/Mg Al-LDO(FP-CP)catalyst lower than 100 ml·m^-3after the reaction from 25 to 400℃.This can effectively reduce the ammonia escape rate in the SCR reaction.Thus,the Mn/Mg Al-LDO(FP-CP)catalyst has potential applications in stationary industrial installations for environmentally friendly ultra-low temperature SCR.

Preparation of N-doped graphite oxide for supercapacitors by NH_(3) cold plasma

In this work,N-doped graphite oxide(GO-P)was prepared by cold plasma treatment of GO using a mixture of NH_(3) and Ar as the working gas.When the ratios of NH_(3):Ar were 1:2,1:3,and 1:4,the specific capacitances of the GO-P(NH_(3):Ar=1:2),GO-P(NH_(3):Ar=1:3),and GO-P(NH_(3):Ar=1:4)were 124.5,187.7,and 134.6 F·g^(-1),respectively,which were 4.7,7.1,and 5.1 times that of GO at the current density of 1 A·g^(-1).The capacitance retention of the GO-P(NH_(3):Ar=1:3)was 80%when it was cycled 1000 times.The characterization results showed that the NH_(3)cold plasma could effectively produce N-doped GO and generate more active defects.The N/C ratio and the contents of pyridinic nitrogen and graphitic nitrogen of the GO-P(NH_(3):Ar=1:3)were the highest.These were conducive to providing pseudocapacitance and reducing the internal resistance of the electrode.In addition,the ID/IGof the GO-P(NH_(3):Ar=1:3)(1.088)was also the highest,indicating the highest number of defects.The results of discharge parameters measurement and in situ optical emission spectroscopy diagnosis of NH_(3) plasma showed that the discharge is the strongest when the ratio of NH_(3):Ar was 1:3,thereby the generated nitrogen active species can effectively promote N-doping.The N-doping and abundant defects were the keys to the excellent electrochemical performance of the GO-P(NH_(3):Ar=1:3).NH_(3) cold plasma is a simple and rapid method to prepare N-doped GO and regulate the N-doping to prepare high-performance supercapacitors.

Plasma-assisted Co/Zr-metal organic framework catalysis of CO_(2)hydrogenation:influence of Co precursors

In this study,Co/Zr-metal organic framework(MOF)precursors were obtained by a roomtemperature liquid-phase precipitation method and the equivalent-volume impregnation method,respectively,using a Zr-MOF as the support,and Co/Zr-MOF-M and Co/Zr-MOF-N catalysts were prepared after calcination in a hydrogen-argon mixture gases(VAr:V_(H_(2))=9:1)at 350℃for 2 h.The catalytic activities of the prepared samples for CO_(2)methanation under atmosphericpressure cold plasma were studied.The results showed that Co/Zr-MOF-M had a good synergistic effect with cold plasma.At a discharge power of 13.0 W,V_(H_(2)):VCO_(2)=4:1 and a gas flow rate of 30 ml·min^(-1),the CO_(2)conversion was 58.9%and the CH4 selectivity reached 94.7%,which was higher than for Co/Zr-MOF-N under plasma(CO_(2)conversion 24.8%,CH4 selectivity 9.8%).X-ray diffraction,scanning electron microscopy,transmission electron microscopy,N_(2)adsorption and desorption(Brunauer-Emmett-Teller)and x-ray photoelectron spectroscopy analysis results showed that Co/Zr-MOF-M and Co/Zr-MOF-N retained a good Zr-MOF framework structure,and the Co oxide was uniformly dispersed on the surface of the Zr-MOF.Compared with Co/Zr-MOF-N,the Co/Zr-MOF-M catalyst has a larger specific surface area and higher Co^(2+)/Cototaland Co/Zr ratios.Additionally,the Co oxide in Co/ZrMOF-M is distributed on the surface of the Zr-MOF in the form of porous particles,which may be the main reason why the catalytic activity of Co/Zr-MOF-M is higher than that of Co/ZrMOF-N.

Prediction of undeformed chip thickness distribution and surface roughness in ultrasonic vibration grinding of inner hole of bearings

Ultrasonic vibration grinding differs from traditional grinding in terms of its material removal mechanism.The randomness of grain-workpiece interaction in ultrasonic vibration grinding can produce variable chips and impact the surface roughness of workpiece.However,previous studies used iterative method to calculate the unformed chip thickness(UCT),which has low computational efficiency.In this study,a symbolic difference method is proposed to calculate the UCT.The UCT distributions are obtained to describe the stochastic interaction characteristics of ultrasonic grinding process.Meanwhile,the UCT distribution characteristics under different machining parameters are analyzed.Then,a surface roughness prediction model is established based on the UCT distribution.Finally,the correctness of the model is verified by experiments.This study provides a quick and accurate method for predicting surface roughness in longitudinal ultrasonic vibration grinding.

Synthesis of Subnanometer-Sized Gold Clusters by a Simple Milling- Mediated Solid Reduction Method

An effective solvent-free method based on a solid-reduction process was developed to fabricate ultrafine gold catalysts. By this method we revealed a strong size-dependent activity of Au species in which subnanometer-sized clusters exhibited the best activity in the hydrogenation of CO_2 to formate, with a turnover number of up to 9278 over 7 h at 90 ℃.

NO hydrogenation to NH3 over FeCu/TiO_(2) catalyst with improved activity

Ammonia is crucial in industry and agriculture, but its production is hindered by environmental concerns and energy-intensive processes. Hence, developing an efficient and environmentally friendly catalyst is imperative. In this study, we employed a straightforward and efficient impregnation technique to create various Cu-doped catalysts. Notably, the optimized 10Fe-8Cu/TiO_(2) catalyst exhibited exceptional catalytic performance in converting NO to NH3, achieving an NO conversion rate exceeding 80% and an NH3 selectivity exceeding 98% at atmospheric pressure and 350 °C. We employed in situ diffuse reflectance Fourier transform infrared spectroscopy and conducted density functional theory calculations to investigate the intermediates and subsequent adsorption. Our findings unequivocally demonstrate that Cu doping enhances the rate-limiting hydrogenation step and lowers the energy barrier for NH3 desorption, thereby resulting in improved NO conversion and enhanced selectivity toward ammonia. This study presents a pioneering approach toward energy-efficient ammonia synthesis and recycling of nitrogen sources.

Two pseudo-polymorphic porous POM-pillared MOFs for sulfide-sulfoxide transformation: Efficient synergistic effects of POM precursors, metal sites and microstructures

Developing sustainable and powerful heterogeneous catalytic systems to convert sulfides into high-value sulfoxide products has become a particularly appealing field and an arduous challenge.In this work,two porous polyoxometalate-pillared metal-organic frameworks,formulated as H_(3n)[Cu_(3)(pidc)_(2)(H_(2)O)_(2.5)]_(2)[PW_(12)O_(40)]_n·x H_(2)O (n=1.5,x=6 for 1,n=1,x=12 for 2;and H_(3)pidc=2-(3-pyridinyl)-1H-imidazole-4,5-dicarboxylic acid),were consciously manufacture and employed for heterogeneously catalyzed sulfide-sulfoxide transformation.Structural analysis shows that 1 and 2 exhibit similar porous frameworks with nearly identical two-dimensional metal-organic layers further pillared by tetradentate POM ligands with different coordination modes,which also result in the porosity of 1 being almost twice that of 2.In catalyzing the conversion of methyl phenyl sulfide (MPS) to methyl phenyl sulfoxide (MPSO),1 can convert nearly 100%of MPS into MPSO within 30 min,while 2 achieved the similar results requires 50 min.The higher activity of 1 may be attributed to its larger channel that can provide more active sites and more efficient mass transfer process.Systematic structure-activity analyses and mechanistic studies revealed dual-reaction pathways driven by POM sites and metal sites assisted by the structural microenvironment.

Nanoparticles targeting at methylases with high correlation to N^(6)-methyladenosine-related lncRNA signatures as potential therapy of kidney clear cell carcinoma

Clear cell renal cell carcinoma(ccRCC)is a heterogeneous malignancy with poor prognosis.Methylation of the N^(6) position of adenosine(m^(6)A),the most common epigenetic modification in both messenger RNAs and noncoding RNAs,has been reported to regulate the initiation and progression of ccRCC.However,whether and how m^(6)A-related long noncoding RNAs(m^(6)ArlncRNAs)signify the progression of ccRCC remain unclear.We found m^(6)ArlncRNAs are effective signatures illustrating immune landscape and risk stratification in ccRCC.We identified two differently expressed m^(6)ArlncRNAs(DEm^(6)ArlncRNAs),AC008870.2 and EMX2OS,as independent risk factors for overall survival of ccRCC patients,by applying stringent variable selection procedure to data from the Cancer Genome Atlas Kidney Renal Clear Cell Carcinoma project.The risk score generated from the DEm^(6)ArlncRNA expression categorizes patients into either high or low-risk groups,between which,enrichment analysis indicated an enrichment in immune-related pathways.Under different DEm^(6)ArlncRNA transcription pattern,the two risk groups differ in immune cell population composition and expression levels of therapy targeting genes.Nanoparticle is satisfactory strategy to delivering therapeutic drugs.For further clinical translation,we designed a novel nanoparticle delivery system packaged STM2457(STM@8P4 NPs),which selectively inhibits AC008870.2-correlated m^(6)A writer.STM@8P4 NPs loaded drug successfully with uniform particle size,long-term stability and high release efficiency.STM@8P4 NPs can easily enter ccRCC cells and showed a highly efficient ccRCC killing activity in vitro.Our results therefore indicate that m^(6)ArlncRNAs expression can depict tumor microenvironment,predict prognosis for ccRCC patient and give hint to therapeutic strategies in ccRCC.